The franchise agreement itself, the franchisor's disclosure material, the entity's governing documents recording ownership, the lease for the premises, and the full cost schedule for opening. Together they show what was bought, who owns it and who decides what.
Keep the commercial file and the immigration file the same file
Buyers often assemble a thorough commercial file and then start a separate, thinner one for the immigration application. It is more efficient to treat them as one, because the same documents answer both sets of questions. The agreement and disclosure show the structure and the cost; the governing documents show ownership; the lease and equipment invoices show what the capital actually bought; the funding records show its lawful source and path. Keep everything from the beginning, including the drafts and the correspondence about changes, because the story of how the enterprise came together is easier to tell when the file was built as it happened rather than reconstructed at the end.
Hypothetical example: Mina is acquiring a commercial window-cleaning company whose seller keeps poor inventory records. An opening assessment separates source-of-funds evidence from proof of the business purchase and future operations. Bank transfers, tax records, sale agreements, lease documents, equipment lists, and customer contracts each answer a different question. Build a transaction ledger before writing the narrative. The common failure is presenting a healthy account balance without showing how funds were lawfully accumulated and how they reached the enterprise. Another is relying on a forecast while omitting the signed documents that show the business can actually begin operating.